Vol 34, No 4 (2018)

The analysis of the influence of the Galactic magnetic field on the trajectory of cosmic rays of extremely high energies (EHECR, E > 10²⁰ eV) detected by Auger and Telescope Array (TA) detectors shows that the magnetar SGR 1900+14 is a potential Galactic source of the EHECR triplet – three events in a circle of radius 2° in the vicinity of the Galactic Center (l = 35°, b = –4°). Magnetar SGR 1900+14 – a neutron star with magnetic field of the order of 10¹⁵ G – was formed as a result of the Supernova outburst 1000…6000 years ago. In our work we investigate possible manifestations of cosmic rays accelerated by the Supernova remnant’s shock, due to their interaction with the molecular clouds of the interstellar medium in the vicinity of Supernova. In particular, the possibility of such a gamma-ray emission model of the newly discovered unidentified TeV gamma-ray source 2HWC J1907+084 is analyzed.

The characteristics of anomalously intense pulses of the pulsar J0242+6256 in the decameter wavelength range are studied in the paper. Observations were made using the Ukrainian T-shaped Radio telescope, second modification (UTR-2) in October 2014. The dispersion measure for the pulsar was refined. For the first time, such characteristics as the scattering time constant, scattering measure, and rotation measure towards the pulsar were determined. Also, the rapid changes in the rotation measure along the profiles of individual anomalously intense pulses were considered. The obtained characteristics show that, despite the small dispersion measure and the close arrangement to the Earth, the scattering measure towards the pulsar is large. Rapid changes in the rotation measure along the pulse profile of this pulsar are possibly due to the presence of a plasma with rapidly changing parameters near the pulsar.

The thermodynamic parameters and parameters of the photospheric magnetic field in the region of chromospheric dual flows in the vicinity of a small pore in the active region NOAA 11024 are presented. The dual chromospheric flows that appeared in the region of abnormal Stokes V profiles of the photospheric lines were associated with the emergence of a new small-scale magnetic flux of positive polarity. Semiempirical photospheric models were obtained by inversion using the SIR program (Stokes Inversion based on Response functions) [42]. Each model contains two components: two thin magnetic flux tubes of different polarity. The magnetic flux has a negative polarity in the first component and positive in the second. The Stokes profiles of the photospheric lines Fe I λ 630.15, 630.25, and 630.35 nm and Ti I λ 630.38 nm from the spectropolarimetric observations with the French–Italian telescope THEMIS (Tenerife, Spain) were used for modeling. The altitudinal dependences of the temperature, line of sight velocity, inclination angle of the magnetic field vector, and azimuth angle in the tubes, as well as the values of the magnetic field strength and macroturbulent velocity, are obtained. The time variations in all parameters of the photosphere are revealed. The new magnetic flux emerged in the region of mixed polarities and was accompanied by the heating of the photosphere and chromosphere. The inferred flux tube models show the temperature enhancement by 400 K in the upper photospheric layers relative to the quiet-Sun model temperature. They indicate a complex, inhomogeneous small-scale structure of the magnetic field and the velocity field. The magnetic field strength in the tubes varies from 0.03 to 0.13 T during the period under consideration. The inclination angles of the magnetic field vector and the azimuth angles strongly differ in magnetic flux tubes and vary in time. The line-of-sight velocity does not exceed 2 km/s. The downflows in the lower layers of the photosphere and the upflows in the upper layers dominate in the first component of the models. In the second component of the model, the material in the upper photosphere is lifted. The macroturbulent velocity in most cases exceeds its value for the unperturbed photosphere. The velocity is greater in the second component of the models. The emergence of the new magnetic flux could lead to the magnetic reconnection and occurrence of a microflare.

A set of nonlinear differential equations describing the parameters during the rise of a thermal (its velocity, radius, and excess temperature) as a function of height and time is numerically solved. It is found that the rise velocity varies nonmonotonically: it increases rapidly at first and its increase rate decreases with the increasing drag of the incoming air; for a long time (tens to thousands of seconds), this velocity remains close to the maximum (approximately 10…180 m/s), and then it decreases relatively slowly (for hundreds to thousands of seconds) to zero. It is shown that the more the thermal is heated and the larger its size, the faster it rises and reaches higher altitudes for a longer time. During the rise, the radius of the thermal increases by a factor of 6…25 depending on its initial size and initial temperature due to the entrained cold air. The greater the current radius value, the higher the increase rate of the thermal radius. The size of a small thermal increases by more times than that of a big thermal. The thermal radius increases until it is completely stopped. Less heated thermals rise more slowly, entrain smaller amounts of cold air, and increase less in size. It is shown that the cooling rate is proportional to the thermal rise velocity and is maximum when the maximum value of this velocity is reached. The warmer thermal cools more rapidly than the less heated one. The thermal cooling rate depends relatively weakly on its initial size. The limitations of the used model (the uniformity and isothermality of the atmosphere and neglect of the effect of thermal radiation, wind, and turbulence on the thermal cooling) are discussed. Despite the limitations, in general, the model is confirmed by the results of observations of the rise of the thermal generated during the explosion of the Chelyabinsk meteoroid.